Muffler



y 1964 c. c. WILLIAMS 3,132,716

MUFFLER Filed March 27, 1962 INVENTOR,

United States Patent Ofiice 3,132,716 Patented. May 12, 1964 MUFFLER Cole C. Williams, Santa Ana, Calif., assignor to L. M.

Cox Manufacturing Co., Inc, Santa Ana, Calif., a corporation of California Filed Mar. 27, 1962, Ser. No. 182,915 4 Claims. (Cl. 181-40) This invention relates to a muffler and more particularly to a mufiier for engines of the type used in model aircraft, boats and cars designated as .049 reed valve engines. Such models have become popular, but the loud, staccato noise is objectionable and has caused restrictive ordinances to be enacted by some communities.

It is therefore the primary object of this invention to reduce the noise of such model engines and overcome the objections thereto.

It is a further object of this invention to accomplish the primary object with a minimum loss of power.

It is a feature of this invention that the device is extremely simple, consisting of only three parts, and is very easy to install on existing engines.

These and other objects, features and advantages will be apparent from the annexed specification, in which:

FIGURE 1 is a side view of the front end of a model airplane with the muffler of this invention installed;

FIGURE 2 is an enlarged view taken on section line 2-2 of FIGURE 1; 9

FIGURE 3 is a section taken along line 3-3 of FIG- URE 2;

FIGURE 4 is an exploded perspective elevation of the mufiler pants; and

FIGURES is a view similar to FIGURE 2 showing the mufiler top reversed.

Referring now more particularly to the drawings, there is shown in FIGURE 1 the nose of an aircraft mounted with an .049 engine 10, a propeller 11 and a coil spring starter 12. The starter is of the type shown in De Groat Patent No. 2,751,898, and is optional, but as stated hereinafter influences the orientation of the mufller top.

The muffler, as best shown in FIGURE 4, consists of a mufiler housing 13, a mufiler top 14 and a muffler spring 15.

The muffler housing 13 comprises a casting 16 having a hexagonal extension 17 with cylindrical bore 18. The casting 16 has an external annular groove 19 which groove is relieved to permit an arcuate slot 20 communicating with the interior of the casting 16 which is an enlarged, as compared to the bore 18, cylindrical bore 21. The bottom of the annular groove is knurled with a plurality of spaced knurls 22.

The top of casting 16 is provided with a re-entr-ant enlarged bore to provide a shoulder 23 forming a seat for the mufiler top 14.

Top 14 is a thin disc having a cylindrical central extension 24 with a circular opening 25 therein.

Spring 15 is formed of flat thin plate bent into a major segment of a cylinder leaving an open space 26 and having one end bent outward to form a tab or handle 27. A detent 28 is formed near the end of spring 15, as shown, by indenting the spring at that point.

The mechanism of this invention comprises the parts shown in FIGURE 4 when used with the model engine shown in the remaining views which disclose an existing .049 model engine.

To install the mulller on the engine the engine is disassembled by removing the cylinder 30 from the engine, installing housing 16 on cylinder boss 31, orienting the opening 26 in an up position on engines having cylinclers mounted sideways to allow ease of engine priming. Muffler top 14 is seated on shoulder 23 with extension 24 either upward or downward. The cylinder 30 is then reinstalled so that mufilertop 14 isseated oncooling fin 32, being the second cooling fin from the bottom of the cylinder. Spring 15 is then installed in annular groove 19 and the assembly is completed. 1

The operation of the above-described device is as follows. To start the engine, spring 15 is rotated in groove 19 to align opening 26 with one of the exhaust ports 40 of the engine to permit priming. The engine is then started and spring 15 is then moved to close the slot 20 for complete mufiling effect or to partially close the same, as desired. Detent 28 acting in knurls 22 will hold the spring as set. Spring 15, being flexible, will expand under pressure of exhaust from the engine to spend the exhaust fumes, but will efiectively muffle the sound, without however, unduly reducing the etficiency of the engine.

As shown in FIGURE 1, if a De Groat starter 12 is used, one end thereof will be seated as shown in FIG- URE l, and the extension 24 of top 14 will extend down into housing 13 as shown in FIGURE 2. If no starter is used the top 14 will be inverted as shown in FIG- URE 5.

While there has been described what is at present considered a preferred embodiment of the present invention, it will be appreciated by those skilled in the art that various changes and modifications can be made therein without departing from the essence of the invention and it is intended to cover herein all such changes and modifications as come Within the true spirit and scope of the appended claims.

I claim:

1. A mufller for a model engine having an open exhaust port comprising: a mufiler housing adapted to surround said port; said housing having an annular groove on its exterior and an opening in said housing adapted to align with said port; a flexible spring seated in said groove, said spring being in the form of a major segment of a cylinder with an outwardly extending tab; said spring providing a gap forming the minor segment of said cylinder and being movable in said groove to align said gap with said opening or to cover said opening as desired.

2. A muffler for a model engine having an open exhaust port comprising: a mufiler housing adapted to surround said port; said housing having an annular groove on its exterior and an opening in said housing adapted to align with said ports; a flexible spring seated in said groove, said spring being in the form of a major segment of a cylinder with an outwardly extending tab; said spring providing a gap forming the minor segment of said cylinder and being movable in said groove to align said gap with said opening or to cover said opening as desired; said annular groove being knurled and said spring having a detent selectively engageable in the knurls.

3. A muffler for a model engine having an open exhaust port comprising: a muffler housing adapted to surround said port; said housing having an annular groove on its exterior and an opening in said housing adapted to align with said port; a flexible spring seated in said groove, said spring being in the form of a major segment of a cylinder with an outwardly extending tab; said spring providing a gap forming the minor segment of said cylinder and being movable said groove to align said gap with said opening or to cover said opening as desired; said mufiler having a top removably seated thereon and having a cylindrical extension, said extension being arranged to extend into or outwardly of said housing as desired.

4. A mufller for a model engine having an open exhaust port comprising: a mufller housing adapted to surround said port; said housing having an annular groove on its exterior and an opening in said housing adapted to align with said port; a flexible spring seated in said groove, said spring being in the form of a major segment of a cylinder with an outwardly extending :tab; saidspring providing a gap forming the minor segment of said cylinder and being movable in said groove to align said gap with said opening or to cover said opening as desired; said annular groove being knurled and said spring having a detent selectively engageable in the knurls; said muffler having a top removably seated thereon and having a cylindrical extension, said extension being arranged to extend. into or outwardly of said housing as desired.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A MUFFLER FOR A MODEL ENGINE HAVING AN OPEN EXHAUST PORT COMPRISING: A MUFFLER HOUSING ADAPTED TO SURROUND SAID PORT; SAID HOUSING HAVING AN ANNULAR GROOVE ON ITS EXTERIOR AND AN OPENING IN SAID HOUSING ADAPTED TO ALIGN WITH SAID PORT; A FLEXIBLE SPRING SEATED IN SAID GROOVE, SAID SPRING BEING IN THE FORM OF A MAJOR SEGMENT OF A CYLINDER WITH AN OUTWARDLY EXTENDING TAB; SAID SPRING PROVIDING A GAP FORMING THE MINOR SEGMENT OF SAID CYLINDER AND BEING MOVABLE IN SAID GROOVE TO ALIGN SAID GAP WITH SAID OPENING OR TO COVER SAID OPENING AS DESIRED. 